In mammography, early detection of breast cancer is dependent upon the ability of the imaging system to resolve characteristic distributions and shapes of small microcalcifications in the breast tissue, since approximately 80% of excised breast cancers show areas of calcification on histologic examination. The medical community has not been satisfied with the imaging performance of standard film-screen in its ability to produce the required quality images. Recently, there has been a desire to resolve 50 micromoles structures with very high detection efficiency. The proposed technique would allow a very high spatial resolution, superior to slow film-screen, with an efficiency greater than fast film- screen. A microstructured scintillator film would allow images to be obtained with a lower dose than film-screen, while the digital nature of the image would permit a wide dynamic range as well as the possibility of image enhancement. The use of a modified low noise amorphous silicon (a- Si:H) detector technology which takes advantage of the high scintillator light output will permit high quality digital imaging systems of 3Ocm x 3Ocm, comparable in area to film-based systems, and much larger than conventional technology currently employed in commercial digital imaging systems. The research proposed here would enable the development of an initial prototype of such a high performance mammographic imaging system. Specifically we propose to develop large-area high resolution structured scintillator screens and low-noise a-Si:H detectors needed to carry out this objective.